Hydrocarbon resins are used in a variety of applications. In elastomeric compositions, for example, hydrocarbon resins are used as a processing aid and to improve the characteristics of elastomeric composition, e.g., in tire components, such as treads and sidewalls, hoses, belts, footwear components, and vibration isolation devices. The selection of ingredients for the commercial formulation of an elastomeric composition depends upon the balance of properties desired, the application, and the end use for the particular application.
Generally, the raw ingredients and materials used in tire compounding impact all tire performance variables, thus, the ingredients must be compatible with the rubbers, not interfere with cure, be easily dispersed in all tire compounds, be cost effective, and not adversely impact tire performance. Rolling resistance, dry and wet skid characteristics, heat buildup, and so on, are important performance characteristics, as well as the ability to improve the endurance of tires used in a wide variety of conditions, such as is required for agricultural tires, aircraft tires, earthmover tires, heavy-duty truck tires, mining tires, motorcycle tires, medium truck tires, and passenger car tires. On the other hand, maintaining ease of processability of the uncured elastomeric composition is also of significant importance. Additionally, the goals of improving air impermeability properties, flex fatigue properties, and the adhesion of the elastomeric composition to adjoining tire components without affecting the processability of the uncured elastomeric composition or while maintaining or improving the physical property performance of the cured elastomeric composition still remain.
Conventionally, various monomers are added to the feed stream to prepare the hydrocarbon polymer modifier (HPM) to achieve target properties to be suitable in the above-mentioned tire applications. It is generally known that cyclopentadiene-based monomers are often used in HPMs for tire applications to increase the softening point (SP) of the HPM, and therefore improve the miscibility of the formulations (and therefore the rolling resistance and grips). However, the addition of cyclopentadiene-based monomers can increase the molecular weight distribution (MWD) or z-average molecular weight (Mz) of the HPM, which may cause the HPM to migrate to the surface of a tire component over time. Therefore, a need exists for an alternative HPM formulation having improved softening point characteristics without increasing the MWD.